

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.TimeUnit;

public class WaitNotify {
    static boolean flag=true;
    static Object lock=new Object();
    public static void main(String[] args) throws Exception{
        Thread waitThread = new Thread(new Wait(), "WaitThread");
        waitThread.start();
        TimeUnit.SECONDS.sleep(1);
        Thread notifyThread = new Thread(new Notify(), "NotifyThread");
        notifyThread.start();
    }
    static class Wait implements Runnable{
        @Override
        public void run(){
            synchronized (lock){
                while(flag){
                    try{
                        System.out.println(Thread.currentThread()+"flag is T. wait@ "+new SimpleDateFormat("HH:mm:ss").format(new Date()));
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                System.out.println(Thread.currentThread()+"flag is F. running@ "+new SimpleDateFormat("HH:mm:ss").format(new Date()));
            }
        }
    }
    static class Notify implements Runnable{
        @Override
        public void run(){
            synchronized (lock){
                        System.out.println(Thread.currentThread()+" hold lock. notify@ "+new SimpleDateFormat("HH:mm:ss").format(new Date()));
                        lock.notifyAll();
                        flag = false;
                        SleepUtils.second(5);
                    }
            synchronized (lock){
                System.out.println(Thread.currentThread()+" hold lock. again.sleep@ "+new SimpleDateFormat("HH:mm:ss").format(new Date()));
                SleepUtils.second(5);
            }
            }
        }
    }
